Patent GB-549052-A (GB)
Title: Improvements relating to railway traffic controlling apparatus
IPC: B61L19/14
Filed: 1941-02-11
Abstract: 549,052. Railway traffic control apparatus. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., and VENNING, C. F. D. Feb. 11, 1941, No. 1855. [Class 105] Apparatus for controlling railway traffic comprises means such as levers for mechanically controlling track points of a number of alternative routes and route-setting switches (as distinguished from switches for the individual operation of signals) on or associated with a track diagram, the arrangement being such that, when the switches are operated to select a desired route, indication is given adjacent to each point lever which requires operation to set up the route. The invention is particularly described with respect to the layout shown on panel PL comprising inter alia route No. 1 over sections AT, BT to station section CT with points P2, P1 normal, route No. 2 from section AT by cross-over to station section DT with points P2, P3 normal and P1 reversed, and route No. 3 from section AT by cross-over and points P3 reversed to station section ET, points P2 being normal and P1 reversed. A signal S with indicator is provided for these routes. Points P1, P2, P3 are respectively operated by levers LP1, LP2, LP3. Adjacent to each lever is a lamp KL1, KL2, KL3 which gives an indication when the corresponding lever requires operation for a selected route. The levers are provided with electromagnetic locks of known kind and circuit arrangements such that a lever in correct position for a selected route cannot be moved therefrom, whilst a lever in wrong position, indicated by the lamp, is free to be moved to correct position and is then locked therein. Route selection is effected in known manner by entrance-exit button, multi-position switch, or as shown, by single switches M1, M2, M3 for each route. The route relays employed have normal and reverse windings 1LR (N), 1LR (R), 2LR (N), 2LR (R) and 3LR (N), 3LR (R) shown at the right, Fig. 3, and are of the kind remaining in the position to which last operated until the other winding is energized. Assuming button M1 operated to set up route No. 1, switch contact M1(R), Fig. 3, is closed and contact M1(N) opened. Route relay winding 1LR(R) is thus energized from terminal B, over 4LR(N) contacts closed if relays of other routes (not hown) are in normal position, wire 41, and contacts 2LR(N)1, 3LR(N)1 closed if route relays of routes Nos. 2 and 3 are in normal position, winding 1LR(R) and contact M1(R) to terminal C. If levers LP1, LP2 are in the requisite normal positions, no indications are given on lamps KL1, KL2, and route No. 1 is set up and signal S cleared, subject to usual interlocking arrangements to prevent setting up conflicting routes and otherwise ensure safe working. If, however, lever LP1 is in its reverse position, indication is given on lamp KL1 as follows. Each lever has contacts NA, RE closed in the normal and reverse positions respectively, and remaining closed during a limited novement of the lever from such positions allowed by the lock, at the end of which limited movements further contacts A, E respectively, are closed. With lever LP1 in reverse position, a circuit, Fig. 4, is closed from terminal B over track relay contacts FTR, BTR (closed if sections FT, BT are unoccupied) closed normal contacts 2LR(N), 3LR(N), lever contact LP1(RE), route-relay contact 1LR(R), and indicator relay winding KL1R to terminal C, contact KL1R1 of this relay then closing the circuit of indicator KL1. When the lever is given limited movement towards normal position, contact LP1(E) is closed, energizing lock magnet LK1 to release the lock and allow completion of movement to normal. When normal position is reached magnet LK1 is de-energized by opening of contact LP1(E) and lamp KL1 is extinguished by opening of contact LP1(BE). Although contact LP1(NA) is now closed, and contact LP1(A) is closed by limited return movement of the lever towards its reverse position, magnet LK1 and relay KL1R remain de-energized and the lever is locked in its normal position since contacts LP1(A) and LP1(NA) are in series with the now open contact 1LR(N), Fig. 4. The Specification gives the circuit arrangements by which signal S is cleared for each of the three routes, and describes a modification in which each route relay winding LR(R) is in series with an LR(N) contact, and each LR(N) winding is associated with a latching coil connected in series with an LR(R) contact in a loop circut bridging the LRN contact and LR(R) winding, the arrangement being in other respects as shown in Fig. 3. Approach locking contacts ALS1 may be provided in the LR(N) circuits as shown.